How refreshing to read a designer saying, "once the clothes are on someone, that person should shine through", and how heartening to have incontrovertible proof that this particular designer has held firm to that belief throughout her 50 years in the industry. The phrase appears in a 1964 Observer piece, where "Britain's youngest, brightest, clothes designer tells – with some surprise – how she captured New York and is about to do so again". The name Mary Quant might spring to mind – but you'd be wrong, and a couple of years adrift. Nope – it's Caroline Charles, who is celebrating a distinctly stylish five decades by publishing what might be termed a "coffee-table book", stuffed with photographs and sprinkled throughout with diary and scrapbook cuttings. But to call it a "coffee-table book" makes it sound like something you might pick up for a 30-minute flick, when it's really much more than that.

There's hardly anything I love quite as much as a good romp through an archive. Caroline Charles – 50 years in fashion certainly provides that but, what it also does, in an unflashy way, is illustrate very vividly the lunatic scheduling, the travelling, and the sheer mind-numbing non-stop grind of life on the fashion circuit. For the 23-year-old Charles that meant a whistle-stop pop and fashion tour of 24 US cities in less than a month. Just reading about it made me want to lie down in a darkened room. But then it was one thing to get the 1960s spotlight to turn its beam on you and quite another to find the stamina, energy and creative ingenuity to keep it there. It must have taken an immense amount of inner steel, determination and personal discipline not to have let it all go to your head and just live in the "hip and happening" moment rather than take the far less sexy long view and build a name and reputation that would inspire respect and admiration half a century later. Charles is clearly made of stern stuff.

Looking at Charles' autumn/winter 2012 collection it's possible to see the evolution from, and references back to, the early days – and also to the 70s, 80s and 90s. The beautiful classic cut, high standard of manufacture and quality fabrics are the foundations upon which the label was built and the reason why so many wardrobes contain at least one Charles piece. Remember Emma Thompson receiving her Oscar for Howards End in a green-beaded bodice and wide trousers? Caroline Charles. I can't help thinking that in terms of the useful "cost per wear" measuring stick, a classic Caroline Charles must be virtually free.

I confess that being somewhat caught up in all the whistles and bells and trumpet-blowing that goes on around the more "disposable" side of fashion I had rather overlooked Caroline Charles but now, having done my research, I can see why she was described as "the thinking woman's designer" when she was awarded her OBE in 2002. There is a thoughtfulness and femininity about everything I see on the rails in her Beauchamp Place HQ or on the website. Maybe there's a hint of the irreplaceable Jean Muir about the simplicity of style and the attention to detail. I have a great fondness for beading and embroidery, which has the disadvantage of sometimes appearing a little fusty unless you choose carefully, but as an investment piece a little black jacket is surprisingly light and almost liquid in the way it falls from the shoulder, and the embroidered neckline is as beautiful at the back as the front. It would, I think, be the cause of a discreet indiscretion of my bank account.

Returning to something John Gale wrote in his remarkably prescient 1964 piece: "She is as the top now, and might stay there 50 years. How has it happened?" Well, not without hard work, persistence and an exceptional talent.